Only because I've used Obbligatos before and liked them. ... if someone else has a great recommendation for these positions I'm all ears.
Your taste and practice are the most important considerations in the field of boutique parts. Personally I for budget side prefer Russian PIO, teflon or paper caps (like K40-Y9, FT-3, MBGA), for more Hi-End - Jentzen, Mundorf... But it is just for me and before considering all impacts.
I'm also curious - why could C301 be left out?
The main problem with all, even very high quality, electrolytic capacitors is big dependence (of their params) on frequency of signal. The more is the frequency, the less suitable the electrolytics are. But sometimes you cannot live without electrolytics - it's all about capacitance values. There is an elegant solution for this. At high frequencies to achieve the same impedance values (sort to say - resistance of the path to AC part of the signal)you can bypass (shunt) an electrolytic capacitor by film (plain) capacitor of much lesser value (the more is the frequency - the less resistance have the capacitor). Then the electrolytic capacitor will work to certain frequency, after that the plain capacitor will catch the duty.
As soon as you are not going to use electrolytic capacitors you don't need bypassing - the Obbligatos are already film (plain) and work fine in full frequencies range.
One can say that it is always good to bypass, even bypassed pair, but for me - it is only waste of efforts and worsening the situation instead of easening it. But in the field of customizing a device for a given taste it is a possible solution too.
